1. pass 1: 2uA on H2 reference cell c1&2 15MHz C3 7.5MHz pass 5 2uA on 3He polarized target c1&2 10MHz C3 9.6MHz
2. pass 1: "tracking eff" defined by the triggers found track vs the triggers does not find track, 0.66 for 2uA on H2 pass 5 this number is about 0.12. The hitting effiency are quite high
3. The chamber hit pattern are plotted in Fig. 1 and Fig. 2 for the single track and multiple track. We can see clearly that there is a shift in the second chamber for the background. Not clear why.
4. From shower only, we can see clearly that there is a peak at the top of preshower. From the study of the correlation with the wire chamber and shower, it is clearly that they are the the positive pions comes from the weak field area from the top of the BigBite magnet. See figures. (We need to shield this!!!!)
5. I did see much difference in the Wire chamber rates, by adding shielding yesterday and tune the beam through compton ...
6. see the shower plot Fig.4,5
Fig.1 1 track hit pattern in chamber 1,2,3 very low luminosity
Fig 2 0 track hit pattern in chamber 1,2,3 very low luminossity
Fig 3. Shower plot, black is with track, red is without track.
Fig 4.cut on pions (preshower), the shower x,y hit pattern, the peak are corresponding to pi+
Fig 5. no cut, shower x,y hit patter, again see clear pion+